From: Oliver Neukum <oneukum@suse.de>
To: Lauri Kasanen <cand@gmx.com>
Cc: jkosina@suse.cz, linux-input@vger.kernel.org,
linux-kernel@vger.kernel.org, ao2@ao2.it, AndrewD207@aol.com
Subject: Re: [PATCH] HID: sony: Enable Gasia third-party PS3 controllers
Date: Tue, 10 Feb 2015 09:14:36 +0100 [thread overview]
Message-ID: <1423556076.19839.3.camel@linux-0dmf.site> (raw)
In-Reply-To: <20150209204414.a4d205be.cand@gmx.com>
On Mon, 2015-02-09 at 20:44 +0200, Lauri Kasanen wrote:
> On Mon, 09 Feb 2015 11:08:01 +0100
> Oliver Neukum <oneukum@suse.de> wrote:
>
> > > + ret = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x02),
> > > + buf2, sizeof(buf2),
> > > + &transfered, USB_CTRL_SET_TIMEOUT);
> >
> > You cannot do this. Even for a single byte DMA on the stack is
> > wrong. Not on all architectures it works at all and you violate
> > the DMA constrainsts. You must use kmalloc().
>
> Hi Oliver,
>
> Does this still apply when using hid_hw_output_report?
Yes. For USB devices hid_hw_output_report() goes to
usbhid_output_report(). That goes to usb_interrupt_msg(),
which passes the buffer pointer. It will then be mapped
for DMA. You must not do that on the stack.
HTH
Oliver
next prev parent reply other threads:[~2015-02-10 8:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-07 13:48 Lauri Kasanen
2015-02-07 15:56 ` Benjamin Tissoires
2015-02-07 16:31 ` Antonio Ospite
2015-02-07 21:48 ` Lauri Kasanen
2015-03-19 10:26 ` David Herrmann
2015-02-09 10:08 ` Oliver Neukum
2015-02-09 18:44 ` Lauri Kasanen
2015-02-10 8:14 ` Oliver Neukum [this message]
2015-03-16 21:10 ` Pavel Machek
2015-03-16 21:37 ` Jiri Kosina
2015-03-19 9:14 ` Oliver Neukum
2015-03-19 9:38 ` Pavel Machek
2015-03-19 9:54 ` Oliver Neukum
2015-03-19 10:12 ` Pavel Machek
2015-03-19 10:29 ` Oliver Neukum
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1423556076.19839.3.camel@linux-0dmf.site \
--to=oneukum@suse.de \
--cc=AndrewD207@aol.com \
--cc=ao2@ao2.it \
--cc=cand@gmx.com \
--cc=jkosina@suse.cz \
--cc=linux-input@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®